1. Field of the Invention
This invention relates to a soot filter for diesel engines, and more particularly to a soot filter which allows accumulated soot to be removed from the filter by "blowing out" the soot from the filter under exhaust gas pressure.
2. Prior Art
Filters basically comprising an encased filter unit having conical-shaped exhaust supply and exhaust discharge pieces, and also having a multitude of parallel channels separated by thin filter walls, whereby half of the channels are open to the exhaust supply piece and thus to the engine exhaust and the other half to the exhaust discharge piece and thus to the tailpipe, with the parallel channels closed off at the opposite end to the open ends, are already known in varied forms in the art. They have one basic problem in common, namely the clogging of the filter walls by soot after a certain period, which causes a high-pressure build-up, resulting in the filter losing its efficiency. This necessitates cleaning the soot deposits, usually meaning in addition to a chemical cleaning, a burn-off of the filter inserts.
Since this procedure usually cannot be done with the filter operating while the engine is running, but only when the motor is shut-off, and since the danger exists that the ceramic material of the filter might be damaged by over-heating during the burn-off, causing complete destruction of the filter, there is a need for a better, simpler, more delicate method of cleaning the filter. Despite the soot burn-off, the problem of the clogged filter walls and increased pressure build-up persists because the remaining particles or ashes from the burn-off are still in the filter, preventing the circulation of the exhaust gases from the unrefined gas channels to the refined gas channels. This is a problem in want of a solution.